Hi @shashwat , as you are looking at the raw values, this level of fluctuation is expected in the distance measurements as we are not doing an averaging in our software. This is something that you would have to implement.
If you are concerned about the measurement not being close to the 40cm/20cm, then that would be antenna delay related. See this response from AndyA regarding using 3 boards in a triangle to do the antenna delay calibration: Calibration issues with UWB - #4 by AndyA